Such mowers are now known the cutting bars of which consist of a flat beam extending crosswise to the direction of work. Disks equipped with blades that rotate around axes directed upwardly extend along the upper part of the flat beam. In addition, the flat beam contains transmission elements which drive the disks in rotation. For this purpose, the flat beam is often made in the form of a fluid-tight housing containing a lubricant for lubrication of the transmission elements.
Since the users want to cut the product to be harvested as close as possible to the ground surface, the thickness of the flat beam must be relatively slight. Concurrently, the width of cutting of the mowers has a tendency to increase. It has therefore been proven in practice that, with relatively large widths of work, the flat beam (that is, in fact, the cutting bar) was a relatively flexible unit in an approximately vertical plane extending crosswise to the direction of work. However, this flexibility may prove detrimental to the life of the cutting bar.
Efforts have therefore been made to stiffen the cutting bar by equipping the flat beam with a large stiffener located behind the beam. However, this solution has several drawbacks.
A first drawback resides in the fact that the width of the flat beam, measured in the direction of work, substantially increases so that the disks cannot sweep the whole upper surface of the beam and the stiffener while rotating. In this manner, it can happen that, under certain working conditions, accumulations of earth and/or plant debris form in places not swept by the disks. These accumulations can prove a hindrance to the smooth flow of the cut product toward the rear of the cutting bar.
A second drawback of the stiffener resides in the fact that it weighs down the cutting bar, which necessitates a lightening mechanism so that the cutting bar will not rest too heavily on the ground.
A third major drawback of the stiffener resides in the fact that, to perform its role of stiffening correctly, the stiffener must be connected as closely as possible to the flat beam. This consequently necessitates a large number of holding elements.
A fourth major drawback of the stiffener resides in the fact that it raises the cost of the cutting bar.